Picosecond Bessel Beam Fabricated Pure,Gold-Coated Silver Nanostructures for Trace-Level Sensing of Multiple Explosives and Hazardous Molecules

A zeroth-order, non-diffracting Bessel beam, generated by picosecond laser pulses (1064 nm, 10 Hz, 30 ps) through an axicon, was utilized to perform pulse energy-dependent (12 mJ, 16 mJ, 20 mJ, 24 mJ) laser ablation of silver (Ag) substrates in air. The fabrication resulted in finger-like Ag nanostructures (NSs) in the sub-200 nm domain and obtained structures were characterized using the FESEM and AFM techniques. Subsequently, we employed those Ag NSs in surface-enhanced Raman spectroscopy (SERS) studies achieving promising sensing results towards trace-level detection of six different hazardous materials (explosive molecules of picric acid (PA) and ammonium nitrate (AN), a pesticide thiram (TH) and the dye molecules of Methylene Blue (MB), Malachite Green (MG), and Nile Blue (NB)) along with a biomolecule (hen egg white lysozyme (HEWL)). The remarkably superior plasmonic behaviour exhibited by the AgNS corresponding to 16 mJ pulse ablation energy was further explored. To accomplish a real-time application-oriented understanding, time-dependent studies were performed utilizing the AgNS prepared with 16 mJ and TH molecule by collecting the SERS data periodically for up to 120 days. The coated AgNSs were prepared with optimized gold (Au) deposition, accomplishing a much lower trace detection in the case of thiram (~50 pM compared to ~50 nM achieved prior to the coating) as well as superior EF up to ~10⁸ (~10⁶ before Au coating). Additionally, these substrates have demonstrated superior stability compared to those obtained before Au coating.     

Thermodynamic and Kinetic Binding Behaviors of Human Serum Albumin to Silver Nanoparticles

A nanoparticle, under biological milieu, is inclined to be combined with various biomolecules, particularly protein, generating an interfacial corona which provides a new biological identity. Herein, the binding interaction between silver nanoparticles (AgNPs) and human serum albumin (HSA) was studied with transmission electron microscopy (TEM), circular dichroism (CD), and multiple spectroscopic techniques. Due to the ground state complex formed mainly through hydrophobic interactions, the fluorescence titration method proved that intrinsic fluorescence for HSA was probably statically quenched by AgNPs. The complete thermodynamic parameters were derived, indicating that the interaction between HSA and AgNPs is an entropy-driven process. Additionally, synchronous fluorescence and CD spectrum results suggested the conformational variation it has upon binding to AgNPs and the α-helix content has HSA visibly decreased. The kinetic experiments proved the double hysteresis effect has in HSA’s binding to the AgNPs surface. Moreover, the binding has between HSA and AgNPs follows the pseudo-second-order kinetic characteristic and fits the Freundlich model for multilayer adsorption. These results facilitate the comprehension about NPs’ underlying biological effects under a physiological environment and promote the secure applications of NPs biologically and medically.     

Quantification of the Hardened Cement Paste Content in Fine Recycled Concrete Aggregates by Means of Salicylic Acid Dissolution

Adherent hardened cement paste attached to recycled concrete aggregates (RCA) generally presents a higher porosity than natural aggregates, which induces a lower porosity in the properties of RCA. The characterization of the adherent hardened cement paste content (HCPC) in the fine RCA would promote better applications of RCA in concrete, but the determination of HCPC in fine RCA is not well established. A simple method based on salicylic acid dissolution was specifically developed to quantify the HCPC in RCA, especially for RCA containing limestone aggregates. The results demonstrated that the soluble fraction in salicylic acid (SFSA) was equal to the HCPC for white cement and slightly lower for grey Portland cement, which was also confirmed by a theoretical approach using modelling the hydration of cement paste with the chemical equations and the stoichiometric ratios. The physical and mechanical properties of RCA (e.g., water absorption) were strongly correlated to the SFSA. For industrial RCA, SFSA did not give the exact value of HCPC, but it was sufficient to correlate HCPC with the other properties of RCA. The water absorption could be estimated with good accuracy for very fine RCA (laboratory-manufactured RCA or industrial RCA) by extrapolating the relationship between water absorption and HCPC, which is very important for concrete formulation.     

克银合剂治疗血热型白疕疗效及对肿瘤坏死因子-α的影响

目的 研究克银合剂治疗血热型白疕(寻常型银屑病)疗效及对肿瘤坏死因子-α(TNF-α)的影响.方法 选取30例寻常型银屑病血热型患者作为研究对象,进行克银合剂治疗,另选取同期接受健康体检的健康人30例作为对照组,研究克银合剂对TNF-α的影响.结果 治疗前TNF-α水平显著高于健康对照组,进行克银合剂治疗后患者症状、体征评分均显著低于治疗前,各项指标水平已经接近对照组.结论 克银合剂能改善寻常型银屑病血热型患者的临床症状,对TNF-α异常也有一定的改善作用.     

Degradation Mechanism and Numerical Simulation of Pervious Concrete under Salt Freezing-Thawing Cycle

In order to explore the occurrence area of pervious concrete freeze-thaw deterioration, the mass loss, strength deterioration, ultrasonic longitudinal wave velocity and dynamic elastic modulus attenuation of pervious concrete under freeze-thaw cycles were measured, and a prediction model of freeze-thaw damage was established. The mechanical properties of hardened cement pastes with the same W/C ratio under freeze-thaw cycles were also measured. Mercury intrusion porosimetry (MIP) was used to measure the pore structure characteristic parameters and pore size distribution changes of cement paste under freeze-thaw cycle, and the microstructure evolution of interfacial transition zone (ITZ) of paste and aggregate was observed by SEM scanning electron microscopy. Finally, a pervious concrete model was established by DEM to analyze the relationship between the number of freeze-thaw cycles and the mesoscopic parameters. The results indicated that the quality, strength and dynamic elastic modulus of pervious concrete deteriorate to different degrees under the conditions of water freezing and salt freezing. The damage sensitivity and strength loss of freeze-thaw damage is greater than the dynamic elastic modulus loss, which is greater than mass loss. In the pervious concrete paste which underwent 100 freeze-thaw cycles, the pore structure and macro strength had no obvious change, and hardened paste and the aggregate-interface-generated defects increased with the increase in freezing and thawing times, indicating that the deterioration of pervious concrete performance under freeze-thaw cycles was closely related to the deterioration of the interface strength of the aggregate and hardened paste. The pervious concrete model established by DEM can accurately simulate the change of the compressive modulus and the strength of pervious concrete during freeze-thaw cycles.     

微卫星多态性检测时银染色和同位素技术比较

为了比较银染色技术与传统的同位素技术在微卫星多态性检测中的优缺点，对ｌｌ８例正常男性基因组ＤＮＡ，用Ｙ染色体特异性微卫星作聚合酶链式反应，经聚丙烯醚胺序列分析后，分别作银染色和同位素检测。结果表明前者重复性好，结果满意，具有经济、对操作者和环境无害、一天即可出结果等优点。对银染色的不足之处进行了探讨。     

丁香开胃贴治疗慢性心功能不全并腹胀临床研究

目的 研究应用丁香开胃贴治疗慢性心功能不全合并腹胀患者的临床效果.方法 在2018年3月—2019年7月选取符合慢性心功能不全合并腹胀的患者100例进行试验,试验中患者都给予了规范的慢性心功能不全治疗方法,但给予的后续治疗不同,患者按此分为了观察组和对照组,观察组患者给予丁香开胃贴,对照组患者给予莫沙必利片,观察患者治...     

重组人表皮细胞生长因子促进慢性创面的愈合

目的观察重组人表皮生长因子（ｒｈＥＧＦ）对慢性创面愈合的影响。方法应用国产ｒｈＥＧＦ，采用自身对照法（对照药物：１％磺胺嘧啶银霜），对６１例慢性创面（烧伤残留肉芽创面３７例，溃疡创面２４例）进行局部治疗。以创面愈合为指标，与对照组平行比较，判读创面愈合时间。结果ｒｈＥＧＦ用于慢性创面的治疗，明显缩短创面愈合时间。肉芽创面愈合时间较对照组缩短约１５天，具有显著性差异（Ｐ＜０．００１）；溃疡创面愈合时间亦有缩短。结论ｒｈＥＧＦ有促进慢性创面愈合的作用     

三种染色方法用于检测聚丙酰胺凝胶中蛋白质的比较

用考马斯亮蓝染色、银染色、铜染色三种方法对同一种蛋白质的灵敏度、快速性进行比较,得出三种蛋白质染色方法的优缺点,为蛋白质电泳染色合理选用不同方法提供依据。     

头低位卧床及饮用含电解银离子水对肠道双歧杆菌的影响

目的观察头低位卧床以及电解银离子 (航天饮用水消毒剂之一 )对肠道双歧杆菌的影响。方法1) 5名健康男性青年进行 2 1d的头低位 - 6°卧床实验 ,收集卧床前后的粪便 ,测双歧杆菌数量。 2 ) 4组小鼠分别饮用不含银纯净水、银含量为 0 .2 0、0 .40、0 .60mg/L的饮水 1月 ,测肠粪中双歧杆菌的数量。3 ) 7名健康男性志愿者 ,连续饮用含银量 0 .2 0mg/L的饮水 16d ,取实验前、饮水第 3、10、16天的粪便 ,测双歧杆菌数量。结果 1 )卧床后被试者粪中双歧杆菌的数量 (lgn/g)较卧床前呈显著性减少 (P <0 .0 1)。 2 )小鼠肠粪混合样中的双歧杆菌数 (lgn/g)与饮水中的银离子含量呈显著性负相关 (r =- 0 .992 ,P <0 .0 1)。 3 )被试者饮用含银离子水后粪中双歧杆菌的含量较饮用前呈显著性减少 (P <0 .0 5 )。结论头低位卧床及饮用含电解银离子水均能导致肠道双歧杆菌数量的减少